Fluid composition



Patented Aug. 8, 1939 FLUID COMPOSITION Ivor M. Colbeth, East Orange, N. J., assignor to The Baker Oastor'Oil Comp ny, Bayonne, N. 1., a corporation of New Jersey. I

No Drawing. Original application July 13, 1935.

Serial No. 31,210.

Divided and this application July 21, 1938, Serial No. 220,455

6 Cla ims. (Cl. 252-5) This invention relates to liquid compositions for use in connection with fluid pressure'operated devices, such as hydraulic brake systemsfor automobiles; etc., for transmitting the pressure. This is a division of my application Serial No.

31,210, filed July 13, 1935.

A liquid composition for such purposes can be prepared in accordance with the present invention which possesses the desirable properties to lo a "remarkable extent and does not require extraordinarily expensive materials or very complicated chemical processes. The type of chemical reactions used for preparing the ingredients are well known and the materials used are readily procurable. Fluid compositions for use in fluid pressure operated devices should possess the desirable properties of not freezing or becoming too viscousv at low temperatures or having portions settle 20 out, should befree ,from decomposition at high.

temperatures, should not have any acids or other ingredients therein that would attack metals, should be capable of being diluted with diluents in which the fluid should be soluble, which dilu- 25 ents themselves do not possess properties that would be objectionable in such hydraulic pressure fluids, should have a high boiling point and low'vapor pressure, should have'a reasonably .uniform viscosity at difierent temperatures, low

cost and ease of manufacture, and should not swell or .otherwise injuriously affect rubber.-

In carrying out this invention an ester is used which is an ester of anacid of the chain series p and a mono-', dior trihydroxy alcohol. The as acid may be acetylated before the ester is formed with the alcohol, ,or' the ester itself may be acetylated after it has been formed, by methods already known. The acetylation. should be caused V to take place at some portion of the chain of the 0 acid or acid radical other than atthecarboxyl group or end of'the chain.\ A mixture of such acetylatedesters may be used, and the acid radicals should replaceall of the H atoms of the alcohol hydroxylsin-forming the esters.

.The underlying principle of this invention is that the esters that are present, in thecomposition are esters that have acetyl groups, CHaCO, substituted for 'Hatoms of hydroxyl groups that are attached to carbon atoms ofthe chain of the 0 acid radicals, which carbon atoms in turn do' not have oxygen atoms attached thereto bydouble bond, and the acetylated acid radicals are substitutedfor the- H atoms of the hydroxyls of the alcohols.

5 Among a very large number of acids that are ture of about 118 C. f

known as acetylated castor oil.

suitable may be mentioned ricinoleic, hydroxystearic, dihydroxy' stearic and ricinic acid, which are especially suitable, and among the large number of alcohols that are suitable may be mentioned methyl, ethyl, butyl, isopropyl, diethylene and triethylene glycols, glycerol, and other mono-, di-, and trialcohols of the fatty acid series which are especially suitable for this invention.

The esters are mixed with a diluent to form the composition that is to be used. The'diluent should have a low viscosity and a low freezing point. It has been found that such diluents as diacetone alcohol and .diethylene glycolether, for

example, are quite satisfactory for this purpose, 5

although many other aliphatic alcohols, such as methyl, ethyl, butyl, isopropyl, etc., which have low viscosity and low freezing points, are suitable.

The following aregivenas specific examples of carrying out the invention, but it is to be unders'tood that they are. given for illustrative purposes and that the invention is not limitedto the f particular. materials, time, temperature, etc.,

given in the examples. v

Ewample*1.- -Castor oil is treated with acetic anhydride by refluxing at the "boiling point of acetic anhydride until all acetic acid that can be combined with the castor oil is combined, Castor oil'consists of about 85% of the estenof ricinoleic 3o acid and glycerol and about 15% of the glycerol esters of 'oleic and linoleic acids with small amounts of hydroxy stearic and stearic acid.

About 400 parts by weight of castor oil is treated with 400 parts by weight of acetic anhydride oiat least 92% strength at a temperav or approximately two hours while theacetic' anhydridethat condenses in the reflux'condenser is returned to the mixer. The mixture is then freed from excess acetic an- 40 hydride and acetic acid that is formed during the reaction, b'y-distilling under vacuum, or is removed inany other convenient way. The last traces of acetic acid can be removed by passing a cm'rent of superheated steam through the mixture until-the condensed steam is free from acidity. .The oilthus treated is commercially Thisacetylated oil can be heated for. several hours to a temperature of 250 C. without any appreciable decomposition. v

The acetylated castor oil is then dissolved in about 50% by volume of diethylene glycol ether.

- acetylation being at a hydroxyl group freezing or becoming too viscous to be used in hydraulic pressure systems, and also without crystallizing.

' Example 2.Approiimately equal parts by weight of acetylated butyl ricinoleate or acetylated ethyl ricinoleate or acetylated dlethylen'e,

glycol ricinoleate, or a mixture of two or more of them, maybe used instead of castor oil, the

acetylated ricinoleates being obtained on themarket or prepared by esterii'yingacetylated ricinoleic acid in the usual way with butyl alcohol or ethyl alcohol or diethylene glycol. Or, ricinoleic acid may be esterifled by treating it with ethyl alcohol, butyl alcohol or diethylene glycol and the ester then acetylated in the usual way. The acetylated product is mixed with a diluent, as describedin Example 1. However, the most convenient source nowknown oi. the glyceride of ricinoleic acid is castorofl.

What is claimed is: 1. A liquid composition-for fluid pressure systems comprising acetylated glyceryl tri-ricinoleate, together with diethylene glycol ether, the of the acid radical not in the carboxyl group. 2. A liquid composition for fluid pressure systems comprising acetylated castol oil, together with diethylehe glycol ether, the acetylation being at a hydroxyl group-of the acid radical not in the carboxyl group.

3. A liquid composition for fluid pressure systems, comprising a substantially completely esterifled ester of a substantially completely acetylated hydroxy fatty acid, said acid containing about 18 carbon atoms, together with diethylene glycol 'ether, the acetylation being at a hydroxyl group of the acid radical not in the carboxyl group.

4. Aliquid' composition for fluid pressure systems, comprising a substantially completely esterifled glycol ester of a substantially completely acetylated hydroxy fatty acid, said acid containing about 18' carbon atoms, together with diethylene glycol ether, the acetylation being at a hydroxyl group of the acid radical not in the carboxyl group.

6. A liquid'composmon for fluid pressure systems, comprising a substantially completely esterifled butyl ester of va substantially completely acetylated hydroxy fatty acid, said acid containing about 18 carbon atoms, together with diethylene glycol ether, the acetlyation-being at ahydroxyl group of the'acid radical not in the carboxyl group.

' IVOR M. COLBEIH; 

